An amazing discovery! If you listen carefully, you'll be able to hear the sound of forty-six years' worth of dedicated Lifenthusiasts all feeling very silly that they didn't run that search already, just in case.

EDIT: Here's a (probably) slightly cheaper predecessor. The smoke seems fairly tenacious, so it will might take an automated search to come up with the least expensive synthesis.

Oh, good -- that's much better. A 9-glider two-engine Cordership synthesis -- that's two new records. And now the table of spaceship recipes under Glider synthesis is incomplete again...

dvgrn wrote:... six gliders for the two switch engines, and seven for the cleanup. It can be improved, um, quite a bit...

For a construction from three directions, here's a more organized and efficient cleanup with five gliders, so 11 gliders for the whole recipe. I haven't run a full gencols (or other) search -- it's quite possible that each pair of gliders on the right can be replaced by a single glider, making a faster 9G recipe:

The idea here is one that often works well for Cordership syntheses. Basically, pretend that the spaceship is already complete, and then find a cheap way to replace any pieces that don't actually exist yet after the initial switch engine construction, using supporting gliders.

But at best I think this method will only tie with AbhpzTa's solution -- a two-glider cleanup seems possible, but maybe not terribly likely.

Like the 3-engine Cordership, the two engines can be stopped by a single glider from behind without releasing any gliders or spaceships. If someone could find the cases where the smallest amount of junk is produced, that would be great:

The above is just the first example that worked, and already it will significantly reduce the cost of projects like the Spaceship Made of Gliders and the eventual quadratic-growth replicator. The next trick will be to come up with the cheapest and cleanest possible one-glider seed for this new Cordership, so that it can be constructed with a slow salvo.

Not too surprisingly, an eater for the 2-engine Cordership turns out to be fairly trivial. EDIT simplified by removing a useless block, and replacing the overkill eater2s -- thanks, Blinkerspawn and Sokwe:

I don't immediately see a good clean 2-engine to swimmer conversion, though -- will have to get some extra glider signals from somewhere to clean up a little extra junk (or find something better than this):

This device could easily send signals forward on both sides to catch up with the Cordership, allowing for different kinds of converters with reasonable-ish recovery time. Could even build silly things like Cordership period multipliers, by using gliders and/or *WSSes to shoot down most Corderships that pass by, leaving only every Nth one.

A catfind, ptbsearch, or Bellman search might possibly locate a clean Heisenburp device based on a transparent block or beehive (or whatever). But until the search is actually done that's more of a dream than a hope.

Sorry, it sometimes does that (especially when a puffer dies sometime between cycles 130 and 150). Cases like that are rare enough that it's not as necessary to filter them out, although filtering them out isn't a bad idea.

I ran a "short" search of about 3 hours while I was away and it found 39 results. 1 was a false positive, the others were puffers. I restarted the search for some reason but the 39 results are available in the text file attached. I did not count how many were duplicates so there might be some duplicates.

Saka wrote:Also, could someone post the part of the script that detects if it is a solution?

It's a bit more complicated than that, unfortunately -- basically half of the script is involved in the ruling out of non-solutions, and when that part is done, it treats everything else as a solution. The part that might be most easily (and useful-ly) changeable would be the population growth cutoff. The line should read

. Setting the number to lower values should give you less puffers with less debris, and higher values should give more puffers and more debris. (To be precise, the number represents the population growth rate per 2880 gens or 20 counts of 96.) Setting it to 0 will give you only ships (if more exist) and false positives.